The present invention generally relates to a vehicle indicator lamp provided with a reflector having a diffusing and reflecting function. The invention is particularly suitable for use in a small vehicle indicator lamp.
In recent years, a vehicle indicator lamp has been proposed (see FIG. 8) wherein a reflective surface 104a of a reflector 104 is formed of a plurality of diffusive and reflective elements 104s such that reflecting light from a light-source bulb 102 forward as diffused light enables a predetermined light distribution pattern to be obtained, in addition to forming a lens 106 of a transparent lens so as to give a sense of transparency to the lamp fixture. However, when this type of structure is employed, some of the diffused and reflected light from the reflective surface 104a is blocked by the light-source bulb 102 and the standing wall 104b of the outer peripheral side of the reflective surface 104a , resulting in a proportional loss of reflected light, as shown in FIG. 8.
This type of loss of reflected light does not pose any particular problem in a large lamp fixture. However, as the lamp fixture is made smaller, the amount of light transmitted from the reflective surface 104a decreases such that the loss of reflected light becomes noticeable. As a result, there is the problem of reduced efficiency of the lamp fixture.
In view of the foregoing problem, an implementation of the present invention provides a small vehicle indicator lamp with a reflector having a diffusing and reflecting function that increasing the lamp fixture efficiency by substantially eliminating the loss of reflected light.
The present invention achieves the foregoing by providing a technique for constructing the reflective surface of the reflector.
According to the present invention, a vehicle indicator lamp is provided with a light-source bulb arranged in a light fixture reference axis extending in the front/rear direction, a reflector having a reflective surface which diffuses and reflects the light forward from the light-source bulb, and a transparent lens in front of the reflector. The reflective surface is formed such that the inner peripheral edge region of the reflective surface radiates reflected light in a direction substantially parallel to the lamp fixture reference axis, while the outer peripheral edge region of the reflective surface radiates reflected light in a direction near the lamp fixture reference axis.
The above-mentioned xe2x80x9ctransparent lensxe2x80x9d may be formed to be transparent across the entire front surface. It may also have a lens function for a portion thereof.
The regions other than the inner peripheral edge region and the outer peripheral edge region in the above-mentioned xe2x80x9creflective surfacexe2x80x9d are not limited to the specific reflective surface shape thereof.
The above-mentioned xe2x80x9cdirection substantially parallel to the lamp fixture reference axisxe2x80x9d includes not only the direction substantially parallel to the lamp fixture reference axis, but also a diagonal direction with respect to the lamp fixture reference axis within a range in which the reflected light from the inner peripheral edge region is not blocked by the light-source bulb.
The vehicle indicator lamp according to the present invention is constructed so as to diffuse and reflect the light forward from the light-source bulb, wherein the reflective surface of the reflector of the vehicle indicator lamp is arranged in the lamp fixture reference axis. The reflective surface is formed such that the inner peripheral edge region thereof radiates reflected light in a direction substantially parallel to the lamp fixture reference axis while the outer peripheral edge region thereof radiates reflected light in a direction near the lamp fixture reference axis. Consequently, the diffused and reflected light from the reflected surface is not blocked by the light-source bulb and the standing wall of the reflective surface outer peripheral side, thereby substantially eliminating the loss of reflected light. Therefore, lamp fixture efficiency is increased even when a lamp fixture is made smaller.
Therefore, a small vehicle indicator lamp provided with a reflector having a diffusing and reflecting function according to the present invention can be realized having increased lamp fixture efficiency due to the substantial elimination of the loss of reflected light.
In the foregoing structure a shape determination method of the reflective surface is not specifically defined. However, the shape of the reflective surface may be determined by dividing the light distribution pattern which should radiate according to the diffused and reflected light into a plurality of pattern regions and calculating the light beam required to obtain the radiated light of the pattern region for each of the pattern regions, while dividing the reflective surface into a plurality of reflective regions corresponding to each of the pattern regions at the solid angle required to obtain the light beam calculated for each of the pattern regions, and setting the gradient distribution of each of these reflective regions such that the reflected light from the reflective region is radiated to each of the pattern regions. Thus, trial and error to obtain the target light distribution pattern is eliminated and a reflector which radiates light forward in the target light distribution pattern may be obtained with one design fabrication. Consequently, lamp fixture development time may be shorted and development cost reduced.
In the foregoing structure, if the construction is such that a condenser lens portion is included that focuses the light from the light-source bulb near the lamp fixture reference axis, wherein the condenser lens is formed on a portion positioned in front of the lamp-source bulb in the transparent lens, the following operation and effect can be achieved.
In a conventional vehicle indicator lamp, since direct light from the light-source bulb 102 toward the transparent lens 106 becomes light which simply expands radially, the direct light contributes almost nothing to the formation of the lamp fixture light distribution pattern and the portion in front of the light-source bulb of the transparent lens 106 is not used efficiently for light distribution control. In contrast, if a condenser lens portion is formed, the portion in front of the light-source bulb of the transparent lens can be used efficiently for light distribution control. As a result, lamp fixture efficiency can be improved and the lamp fixture can be made that much smaller. In addition, when observing the lamp fixture from the front, the condenser lens portion appears to float on the lens surface and the back of the reflective surface is visible through the surrounding transparent lens portion, thereby giving a three-dimensional appearance and a sense of depth to the lamp fixture.
When a light distribution control function is added to both the lens and the reflector in this way, it generally becomes difficult to accurately control the light distribution of the lamp fixture. However, since the condenser lens portion is formed on the portion in front of the light-source bulb and the portion in front of the reflective surface is a transparent lens portion, functions can be divided to some extent with the focusing of the direct light from the light-source bulb controlled by the condenser lens portion, and the diffusion and reflection of the admitted light from the light-source bulb controlled by the reflective surface. Therefore, light diffusion of the lamp fixture is able to be controlled relatively accurately.
In this case, if the reflective surface is formed so as to admit substantially all of the diffused and reflected light from the reflective surface to a transparent lens portion, the functions can be almost entirely divided with direct light focus controlled by the condenser lens portion and diffusion and reflection controlled by the reflective surface. As a result, the light distribution of the lamp fixture can be controlled accurately.
The shape setting method of the condenser lens portion is not specifically limited. However, if the shape is set by dividing the light distribution pattern which should be radiated according to the transparent light of the condenser lens portion into a plurality of pattern regions and calculating the light beam required to obtain the radiated light of the pattern region for each of these pattern regions, while dividing the condenser lens portion into the plurality of lens regions corresponding to each of the pattern regions at the solid angle required to obtain the light beam calculated for each of the pattern regions, and setting the prism vertical angle distribution of each of these lens regions such that the transparent light from the lens region is radiated to each of the pattern regions, then trial and error to obtain the target light distribution pattern is eliminated and a lens which radiates forward of the lamp fixture with the target light distribution pattern is able to be obtained with one design fabrication.
An embodiment of the present invention will be hereinafter described with reference to the drawings.